Conventional aircraft execute turns using ailerons, which are aerodynamic devices that work as a synchronized opposing pair along the trailing edges of opposing wings. A first aileron rotates upward to give a first wing a downward aerodynamic force and the second aileron simultaneously rotates downward to give the second wing an upward force to roll the aircraft, thereby rotating the lift vector and so creating a horizontal component of lift that moves the aircraft horizontally to execute the turn. Synchronized ailerons produce differential profile drag, producing a reverse yaw effect that must be compensated for with a rudder.
Many crashes with loss of life have resulted from low speed stalls on final approach to landing, because only a highly-skilled pilot can resist the normal reaction to a wing dropping. The normal reaction is to turn the yoke in the direction opposite the low wing, which would normally (at higher speeds and altitudes) be the correct response. In response to the reaction, the low wing gains additional lift from the increase in camber caused by the drooping aileron, and the raised aileron on the opposite wing reduces lift on that wing. These combined forces cause the wings to become level. However, when the aircraft has slowed to minimum approach speed, and a wing drops, the normal reaction of turning the yoke in the opposite direction increases the camber of the low, slow wing and so increases drag on that wing, which is likely to cause the wing to stall and induce a tailspin from which even a skilled pilot could not recover at final-approach altitude. The correct procedure in this case is to lower the nose and increase power to avoid the stall. The skilled pilot must recognize that only increasing speed will allow the aircraft to maintain level flight and normal glide path to escape a low-altitude dropped wing stall using conventional ailerons.
Thus, there is a need for an aileron system that will cause the aircraft to avoid a low-speed dropped-wing stall in response to the intuitive reaction of a relatively unskilled pilot rather than require the reasoned reaction of a skilled pilot.